runtimelog: port docker compose log streamer to the reconciler

[nicks]

Hello @milas,

Please review the following commits I made in branch nicks/dclogs:

467df7cf94c856c71eef2bc61a016a26b553005e (2022-05-18 15:00:43 -0400) runtimelog: port docker compose log streamer to the reconciler

Code review reminders, by giving a LGTM you attest that:

• Commits are adequately tested
• Code is easy to understand and conforms to style guides
• Incomplete code is marked with TODOs
• Code is suitably instrumented with logging and metrics

[nicks]

a lot of this is just moving code around and writing better tests for it. i'm hoping this will be a lot more robust in general when interoperating with docker-compose.